


Staying in the Lines

by skerb



Category: Undertale (Video Game)
Genre: Blushing, Fontcest, Kedgeup, M/M, Makeup, Sans/Underfell Papyrus (Undertale), Shy Sans (Undertale), Underfell Papyrus (Undertale), Unresolved Sexual Tension, background spicykustard
Language: English
Status: Completed
Published: 2020-07-21
Updated: 2020-07-21
Packaged: 2021-03-05 05:54:51
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,550
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25419547
Author URL: https://archiveofourown.org/users/skerb/pseuds/skerb
Summary: Sans takes Edge up on his offer to pencil him in.
Relationships: Kedgeup - Relationship, Papyrus/Sans (Undertale)
Comments: 40
Kudos: 137





	Staying in the Lines

“Don’t you get tired of that?”

Sans has been watching Edge for a while from the entrance to his bedroom. It’s a daily routine, one marked with the fascinations of the nefarious skeleton brothers. He’s made a habit of staying over, going home to visit Papyrus, before coming back for the night. It’s been an interesting endeavour to see their daily rituals, something Sans thought he might never get used to.

Namely, this morning when he wakes and finds Edge in the process of lining his eye sockets with crimson pencil. A few things go through Sans’ head at once. One, it’s early, far too early for Red to be up, though the bonehead groaned a protest when Sans shimmied out of bed. Two, Sans isn’t quite sure what timeline this is that he even woke up this early. And finally, he caught Edge without his signature eyeliner.

Well, one side, anyway.

Edge seems taken aback by his enquiry. It’s not judgemental. Sans had judged far weaker crimes than clearing out the local craft store of their #924 crimson red coloured pencils. Normal human makeup just doesn’t adhere to bone and tends to stain horribly even if it does. At least, that’s what Edge said after giving him a full debriefing of the daily occurrence sometime after they’d first met.

“Hardly,” Edge replies after giving Sans an assessing look, then raises the pocket mirror up to line out his other eye socket. “Why? Are you curious?”

Sans does the full-body equivalent of a shrug, flapping his hands in his pockets for emphasis like a penguin. “I dunno. Maybe a little bit.”

“I could do you, if you want.”

A shock of powdery blue races up Sans’ throat, betraying how he takes it. He eyes Edge on his bed, inviting and relaxed.

He pretends he doesn’t feel too interested, but he’ll play along. Why not. The kid already dressed him up to be a sugar skull one year. It was kind of fun. He’ll endure a longer bathtime to scrub it off later.

Edge looks supremely invested in the offer. Sans tries not to think about how it might lead to sex. Of course it won’t. His face continues to feel hot, though. Edge has been looking at him this entire time. Sans makes another show of shrugging, then carefully sits at Edge’s side on the bed and waits for his turn.

As it stands, Edge blocks him in on his side of the bed. When he’s finished, he pivots so they’re face-to-face, and Sans can’t quite shake how he feels about that. Nonetheless, he sends Edge his toothiest grin, barely awake but for the promise of being close to such a cool guy. Edge definitely has an effect on him.

The tension in the room is different now. Sans tries to look anywhere but at Edge’s face so he doesn’t see the clear want in his eyes. It makes a heated shiver travel down Sans’ spine to be under that gaze. It’s kind of intoxicating to be the centre of Edge’s attention like this.

Edge puts the pocket mirror back into his inventory. Sans tries not to tremble, no matter how much his soul wants to drum in his chest like rolling thunder. He sighs gently, anticipating that jolt of adrenaline when Edge uses the tips of his long fingers to urge him to lift his chin. He just barely touches him and Sans already has the vapours.

It doesn’t help that when Edge silently asks him to submit to him like this, Sans folds like a cheap lawn chair. His shoulders hunch, his hoodie slinking negligibly down to his elbows as he’s made to sit up. When Edge’s thumb grazes against the side of his throat, the air’s charged with something heavy and warm, and boy, Sans can feel it. He feels flushed.

Edge savours his reactions like he’s meticulously sizing up a pretty specimen. Sans’ gaze moves to Edge’s eyes, burning brightly and lined by that brilliant crimson, perfectly selected to match his magic. Sans’ soul beats nervously from how close he’s gotten, leaned forward to bring the pencil close.

Sans can detect the hint of soap Edge uses. It lingers, filling his head with warm thoughts. He can feel it high on his cheekbones. God, he’s probably blushing. This was probably a dumb idea. He can’t tear his eyes away.

“Are you ready, Sans?”

Edge looks at him as though to assess the best angle to approach. When he leans in closer, Sans’ breath hitches, unable to contain his excitement as he grips the corner of the mattress. Sans has the uncontrollable urge to lean forward for a kiss. He can barely feel it, his body trembling just a little as gravity pulls him with invisible strings.

With the haste and softness of all his desires, Sans manages to eke out a quiet, _“Yes,”_ to Edge’s question.

Edge’s fingertips rest on his jaw where Sans wants them to be. A glint of something devious in his gaze catches Sans’ eye, rendering him speechless, though Edge stops him from pushing forward with a gentle touch to his throat.

He wants a kiss so much it _burns._

“Ah-ah,” Edge chastises gently. Sans feels it in his soul. “Stay still.”

He seems extremely pleased about that. He must be savouring this, watching Sans squirm under the pressure of his own raging libido. Sans sighs out, trying to regain some composure, because wow, he suddenly needs eight cold showers. He complies, though, remaining frozen in place. He wants for nothing more than for Edge to do whatever he wants to him.

He attempts not to tremble so much when Edge’s grip firms at his jaw to keep him in place. It’s where he wants him to be, and the unnecessary force draws Sans tight like a bow. He’s got it big for just a hint of control, every ounce of Edge careful and encouraging at once.

His face is hazy-hot and he can’t control it. When Edge leans in to finally bring the crimson pencil close, Sans keeps his eyes open, watching as Edge focuses. He’s still not used to being under such a rapturous gaze that it makes his body feel like warm jelly.

The pencil glides over the rim of his eye socket, gentle yet firm. Just like Edge. It’s a foreign feeling, as Sans isn’t used to such glamorous tendencies like his brother or certain entertainment robots. His grip tightens on the cushiony mattress, slowly feeling the urge to filter his frustration into meaningless gestures.

He can feel every ounce of control in Edge’s hand, not a waver in sight. Sans slowly exhales, just in case. It’s pleasant, the sensation of it even and smooth. He needs to relax. As the pencil continues to move, Sans starts to feel its pressure somewhere else. 

Edge is careful enough not to disturb the magic barrier within Sans’ eye sockets. He has all the control in this situation, which makes Sans’ soul drum up anew. He holds his breath, stealing short little gusts when Edge’s breath brushes his face. He’s definitely close enough to kiss now.

He doesn’t do it. When the first eye is finished, he lets up, allowing Sans his breathing space. Sans looks around like he’s waking from a dream and blinks when Edge offers to see himself in the pocket mirror.

It looks… like eyeliner. Yep. Wow, he can’t stop thinking about Edge holding him down. It’s too early for this.

“Ready for another?” Edge asks. There’s a slight rumble in his voice from the deep purr he’s trying to mask.

Dumbly, Sans slowly nods and tries to hand back the mirror, but Edge just takes him by the jaw again, throwing another anticipatory shudder down Sans’ spine.

“O-oh. Ok,” Sans manages to whisper.

Edge eases his face so he can access his other eye. It’s surprisingly heady, sinking into all Sans’ private fantasies. As he thinks about it, Sans swallows hard and tries to dispel the magic suffusing his bones, in between his joints and under his eyes. It doesn’t work as well as he hopes.

Soon, though it seems like a pleasant eternity with Edge in his personal space, Sans’ other eye is lined to match. He can’t control it when Edge lets his fingers slip from his chin to his throat, the broken sound caught around a swallow. Flustered, Sans just stares at Edge until he’s urged to look at the pocket mirror in his hand.

Ok. It looks better as a pair, Sans relents. Though honestly, it looks like Edge was enjoying his reaction. He allows the mirror to sink out of view again, idly curling his fingers in his lap when Edge cups the side of his face.

Oh. There’s the kiss. It’s gentle and sweet, a bare brush of teeth against teeth. No sloppiness, no tongue, just something to keep Sans going until breakfast is ready. He barely gets a taste of him when Edge pulls away much too soon, thumbing over the ridge of Sans’ cheekbone with a pleased, assessing look.

His next whisper is uttered so low that it’s just for him.

It affects Sans in more ways than one when Edge speaks, indulgent.

“Red looks good on you.”

**Author's Note:**

> inspired by beetle's [eyeliner art](https://twitter.com/popat0_chisps/status/1184325848385626112?s=19) and enneadodeca for reminding me of it. ;u;
> 
> BEETLE DREW ART YOU GUYS, [**AAAAAAAAAAAAAAAAAAAAAAAA**](https://twitter.com/beetleevil/status/1293787032960086017?s=20)


End file.
